<template>
  <div class="xtx-city" ref="target">
    <div class="select" @click="toggle" :class="{ active: visible }">
      <span v-if="fullLocation">{{ fullLocation }}</span>
      <span v-else class="placeholder">{{ placeholder }}</span>
      <span class="value"></span>
      <i class="iconfont icon-angle-down"></i>
    </div>
    <div class="option" v-if="visible">
      <div v-if="loading" class="loading"></div>
      <template v-else>
        <span
          class="ellipsis"
          @click="changeItem(item)"
          v-for="item in currList"
          :key="item.code"
          >{{ item.name }}</span
        >
      </template>
    </div>
  </div>
</template>

<script>
import { computed, ref, reactive } from 'vue'
import { onClickOutside } from '@vueuse/core'
import axios from 'axios'
export default {
  name: 'XtxCity',
  props: {
    fullLocation: {
      type: String,
      default: ''
    },
    placeholder: {
      type: String,
      default: '请选择配送地址'
    }
  },
  setup (props, { emit }) {
    const target = ref(null)
    const visible = ref(false)

    // 获取城市数据,显示当前地方列表
    // 2. 显示和隐藏函数（为什么是函数，做更多事情）
    const loading = ref(false)
    const cityData = ref([])
    const open = () => {
      visible.value = true

      loading.value = true

      // 清空changeResult中的内容
      for (const key in changeResult) {
        changeResult[key] = ''
      }

      getCityData().then(data => {
        loading.value = false

        cityData.value = data
      })
    }

    const close = () => {
      visible.value = false
    }

    const toggle = () => {
      visible.value ? close() : open()
    }

    onClickOutside(target, () => close())

    // 获取城市数据
    // 1. 数据在哪里？https://yjy-oss-files.oss-cn-zhangjiakou.aliyuncs.com/tuxian/area.json
    // 2. 何时获取？打开城市列表的时候，做个内存中缓存
    // 3. 怎么使用数据？定义计算属性，根据点击的省份城市展示
    const getCityData = () => {
      return new Promise((resolve, reject) => {
        if (window.cityData) {
          resolve(window.cityData)
        } else {
          axios
            .get(
              'https://yjy-oss-files.oss-cn-zhangjiakou.aliyuncs.com/tuxian/area.json'
            )
            .then(res => {
              window.cityData = res.data

              resolve(window.cityData)
            })
        }
      })
    }

    const changeResult = reactive({
      provinceCode: '',
      provinceName: '',
      cityCode: '',
      cityName: '',
      countyCode: '',
      countyName: ''
    })

    // 定义计算属性
    const currList = computed(() => {
      let currList = cityData.value

      if (changeResult.provinceCode && changeResult.provinceName) {
        currList = currList.find(p => p.code === changeResult.provinceCode)
          .areaList
      }

      if (changeResult.cityCode && changeResult.cityName) {
        currList = currList.find(p => p.code === changeResult.cityCode).areaList
      }

      // TODO 根据点击的省份城市获取对应的列表
      return currList
    })

    const changeItem = item => {
      if (item.level === 0) {
        changeResult.provinceCode = item.code
        changeResult.provinceName = item.name
      } else if (item.level === 1) {
        changeResult.cityCode = item.code
        changeResult.cityName = item.name
      } else if (item.level === 2) {
        changeResult.countyCode = item.code
        changeResult.countyName = item.name
        // 完整路径
        changeResult.fullLocation = `${changeResult.provinceName} ${changeResult.cityName} ${changeResult.countyName}`
        // 这是最后一级，选完了，关闭对话框，通知父组件数据
        close()
        emit('change', changeResult)
      }
    }

    return {
      visible,
      target,
      toggle,
      loading,
      currList,
      changeItem
    }
  }
}
</script>

<style scoped lang="less">
.xtx-city {
  display: inline-block;
  position: relative;
  z-index: 400;
  .select {
    border: 1px solid #e4e4e4;
    height: 30px;
    padding: 0 5px;
    line-height: 28px;
    cursor: pointer;
    &.active {
      background: #fff;
    }
    .placeholder {
      color: #999;
    }
    .value {
      color: #666;
      font-size: 12px;
    }
    i {
      font-size: 12px;
      margin-left: 5px;
    }
  }
  .option {
    width: 542px;
    border: 1px solid #e4e4e4;
    position: absolute;
    left: 0;
    top: 29px;
    background: #fff;
    min-height: 30px;
    line-height: 30px;
    display: flex;
    flex-wrap: wrap;
    padding: 10px;
    > span {
      width: 130px;
      text-align: center;
      cursor: pointer;
      border-radius: 4px;
      padding: 0 3px;
      &:hover {
        background: #f5f5f5;
      }
    }
    // 省略...
    .loading {
      height: 290px;
      width: 100%;
      background: url(../../assets/images/loading.gif) no-repeat center;
    }
  }
}
</style>
